Repair firms contacted by ChannelNews said it often serviced laptops suffering low battery life within one to two years of purchase.

“We find there is a direct correlation between the amount of software running on the machine at any given time and the life a user should expect from it,” executives from the Geek Squadsaid.

It recommends lowering screen brightness, turning off features such as bluetooth and wi-fi when not in use, and making use of power-saving software, which is installed in many Windows and Mac-based devices, to maximise battery life.

Only Apple’s Macbook Pro lived up to its 10-hour battery life claim in the tests, which included watching films and using the net via wi-fi.

Models by Dell, Acer, Lenovo and HP came in with around half the advertised battery life.

Manufacturers tend to test in “optimum conditions”, one analyst said.

“Battery life metrics on consumer electronics devices such as laptops are typically measured in optimum conditions, which maximise performance,” Ben Wood from CCS Insight told the BBC.

“There are lots of variables when it comes to real world use such as how bright the screen is and what applications you are using, which can have a major impact on battery performance.”
‘Different mileage’

Dell also told Which? it was difficult to define average laptop use.

“Every individual uses their PC differently,” it said.

“It’s similar to how different people driving the same car will get different mileage depending on how they drive.”

David Richards has been writing about technology for more than 30 years. A former Fleet Street, Journalist He wrote the Award Winning Series on the Federated Ships Painters + Dockers Union for the Bulletin that led to a Royal Commission. He is also a Logie Winner. for Outstanding Contribution To TV Journalism with a story called The Werribee Affair. In 1997, he built the largest Australian technology media Company and prior to that the third largest PR Company that became the foundation Company for Ogilvy PR. Today he writes about technology and the impact on both business and consumers.